That's where Robber of the Rich comes to play: If your opponent has more cards in hand than you (a simple task given how low the curves often are) you get to steal cards from your opponent
These will transform after you fulfill some kind of condition on the card, usually either an activated ability (i.e., paying to exile Terra, Magical Adept) or triggered ability (i.e., having six permanents in the yard for Exdeath, Void Warlock at end of turn)
Aethersquall Ancient: Because EDH
Chain Assassination + Distract the Guards + Eagle Vision + Petty Larceny + Restart Sequence Each of these cards, if you can get them down for the 2-mana freerunning cost, is way above rate
Which set should you never touch with a 10-foot pole (cough Homelands cough)
Blue and black aggro decks have existed in the past, but these are less common